Nature and characteristics of the binding of oestradiol-17beta to a uterine macromolecular fraction

The binding of oestradiol-17beta to two proteins, namely serum albumin and a uterus fraction, was studied in vitro. The former protein has a physiological function in the transport of the hormone and the latter is involved in the selective uptake of the steroid by the target organ. The uterus fraction shows a high degree of stereospecificity for the binding of the steroid. Cortisone, oestradiol-17alpha and testosterone are bound negligibly and progesterone to a much smaller extent than is oestradiol-17beta. This property is in contrast with the wide variety of ligands bound by the serum albumin. The temperature and the presence of the steroid influence markedly the binding properties. Oestradiol binding to the uterus fraction is optimum at 37 degrees and at pH7-8.5. It is markedly decreased at pH values above or below this range, suggesting stringent conformational requirements. The tissue ;receptor' protein is a macromolecule with a minimum molecular weight of 100000. The protein moiety is essential for the binding function. The probable concentration of the total binding sites for oestradiol in the ovariectomized-rat uterus cytoplasmic fraction as determined in vitro is about 1mmum at a steroid concentration of 50mmum.

Low dose gossypol for male contraception

AIM

To ascertain whether the side effects of gossypol, hypokalemia and irreversibility, could be avoided on dose reduction.

METHODS

Seventy-seven male volunteers were divided into 3 groups: control (22 cases), 10 mg gossypol (29 cases) and 12.5 mg (26 cases). Serum levels of testosterone, FSH and LH were measured by RIA and potassium by flame photometry. Sperm counts and motility were examined before and regularly after treatment for the evaluation of contraceptive efficacy.

RESULTS

The average sperm density and motility started to decrease significantly by the end of month 2 of medication and gradually reached the infertility levels (< 4 million/mL) in both treated groups. After that the 10 mg group was asked to take the same dose every other day for up to a total observation period of 16-18 months for the maintenance of infertility. Subjects in the 12.5 mg group did not take gossypol any more so as to observe the length of the loading dose required, but in a few, a maintenance dose of 12.5 mg every other day was instituted for a few more months. In both treated groups, none of the spouses was pregnant during the maintenance dose period. Serum levels of potassium, FSH, LH and testosterone were not significantly changed and not a single volunteer complained of myoasthenia. After cessation of drug administration, the semen data returned to pretreatment levels.

CONCLUSION

A regimen with 10 or 12.5 mg of gossypol as the daily loading dose and 35 or 43.75 mg as the weekly maintenance dose could induce infertility in male volunteers without developing hypokalemia or irreversibility.

Gossypol blood levels and inhibition of spermatogenesis in men taking gossypol as a contraceptive. A multicenter, international, dose-finding study

The safety and efficacy of gossypol continues to be controversial. The aim of this study was to evaluate gossypol as a contraceptive pill for men at doses lower than those previously prescribed and in men from various ethnic origin. A total of 151 men from Brazil, Nigeria, Kenya, and China were divided into two groups. Both groups received 15 mg gossypol/day for 12 or 16 weeks to reach spermatogenesis suppression. Subjects were then randomized to either 7.5 or 10 mg/day for 40 weeks. In addition, 51 men were enrolled as a control group. In all, 81 subjects attained spermatogenesis suppression. Only one man discontinued treatment because of tiredness. Potassium levels fluctuated within the normal range. FSH increased consistently. Testicular volume decreased, but after discontinuation, values returned to levels not statistically different from admission. Of 19 subjects on the 7.5 mg/day dose group, 12 recovered sperm counts >20 million/mL within 12 months of discontinuing gossypol. In the 10 mg/day group, sperm counts recovered in only 10 of 24 subjects. Eight of the 43 patients remained azoospermic 1 year after stopping gossypol. All men diagnosed with varicocele failed to reverse spermatogenesis suppression. Gossypol blood levels indicated that sperm suppression occurs independently of concentration, whereas spermatogenesis recovery appears to be concentration-dependent. Gossypol may become a medical alternative to surgical vasectomy when the delay in onset of infertility is acceptable. When taken for 1 year, gossypol causes no reduction in sexual desire or frequency of intercourse. The possibility of reversal, occurring in 51% of the men on this regimen within 1 year after stopping gossypol, is an advantage of this compound as compared with surgical sterilization in many parts of the world.

Liability concerns in contraceptive research and development

The history of liability claims in the US against contraceptive products is among the issues that discourage manufacturers from investing in discovery and development in this field. Other factors are the high cost of new drug development, elevated insurance rates for contraceptives, and the desire to avoid controversy that can disturb corporate tranquility. General features of the American legal system influence the large number and cost of product liability claims in the US compared to Europe. These differences pertain to issues such as the role of judges, how lawyers receive their compensation, and the use of expert scientific testimony. The history of litigation in the US against pharmaceutical products and devices pertaining to women's health suggests that interventions that involve the reproductive system are held to different standards or elicit different emotional responses than other pharmaceutical products or devices.

Regulation of serotonin-induced calcium uptake in Spisula oocytes by tricyclic antidepressants

The effect of tricyclic antidepressants on 5-hydroxytryptamine (serotonin or 5-HT)-induced maturation and Ca2+ uptake in Spisula oocytes was determined. The drugs at a concentration of 20 microM completely blocked germinal vesicle breakdown and 45Ca2+ uptake by Spisula oocytes. The order of effectiveness of the antidepressants were imipramine > desipramine > clomipramine. The present findings suggest that the action of tricyclic antidepressants is to regulate Ca2+ uptake into 5-HT-responsive cells.

Trends in population and contraception

There has been an explosion in contraceptive use in the past 30 years. In 1960-65, the level of contraceptive use in the developing countries of Asia, Latin America and Africa represented about 9% of married couples of reproductive age. In the 1990s use of contraception in developing countries comprises over 50% of couples and contraceptive prevalence is increasing each year. Total fertility rates for the developing world have already fallen from over 6, where they were in 1960 to about 4, halfway toward the replacement level of 2.1. The United Nations projects that during this decade, over 90 million people will be added each year to world population. If this projection is not to be exceeded, prodigious supplies of contraceptives will have to be available at affordable cost to the people of developing countries, where 94% of this population increase will occur. New technology alone will not guarantee this success, but it would help ensure that people are able to meet their fertility objectives.

Norplant implants: the mechanism of contraceptive action

OBJECTIVE

To determine if fertilization occurs unnoticed among Norplant users who are ovulatory.

DESIGN

Serial blood samples were obtained during 1 month from sexually active Norplant users experiencing regular menstrual bleeding patterns and a control group of noncontracepting women trying to conceive. The sequential blood samples were assayed for the presence of human chorionic gonadotropin (hCG).

SETTING

All samples were obtained from women receiving contraceptive service and health care at the Center for Research and Services in Human Reproduction and Contraception, Santo Domingo, The Dominican Republic. Assays for hCG were performed at the Department of Biomedical Sciences, University of Tampere, Finland.

PATIENTS, PARTICIPANTS

A total of 32 women using Norplant implants were enrolled in the treatment group, and 20 women of proven fertility who were attempting to conceive served as a control group.

INTERVENTIONS

Duration of Norplant use was as follows: 4 in the 2nd year of use, 13 in the 3rd year, 11 in the 4th year, 3 in the 5th year, and 1 in the 7th year.

MAIN OUTCOME MEASURE

The determination of pregnancy was based on the presence of hCG in the luteal phase, using a sensitive and specific immunoenzymatic assay that can detect dimeric hCG as early as 7 days after ovulation.

RESULTS

Nine pregnancies were detected. All were in the control group trying to conceive. Six of these advanced to clinical pregnancies, and three did not proceed beyond the next expected menses. None of the Norplant users had evidence of hCG production, whether the observed cycles were anovulatory or ovulatory. The probability of finding no pregnancies in the ovulatory months at risk among Norplant users is between 1 in 50 and 1 in 150,000. The null hypothesis that Norplant users conceive at a natural rate can be rejected at the 0.05 level.

CONCLUSION

Interruption of early pregnancy (menstrual abortion) does not play a role in the mechanism of action of Norplant contraceptive implants.

Inactivation of human immunodeficiency virus in vitro by gossypol

Gossypol, a polyphenolic aldehyde extracted from cottonseed, is a male anti-fertility agent which has been reported to have anti-viral activity. In this paper we report that gossypol inactivates human immunodeficiency virus (HIV) in an in vitro system. Following exposure of cell-free incubates of HIV to 100 uM gossypol, ultracentrifugation and inoculation of the washed pellet onto H9 cells, there is no evidence of elevated reverse transcriptase activity over 21 days. Treatment with lower concentrations of gossypol reduces the peak and lengthens the time to maximal reverse transcriptase activity compared with control cultures. These observations suggest that gossypol could be used as a vaginal spermicidal/virucidal agent. The mechanism of the in vitro anti-viral action as well as the effect of orally administered gossypol on the infectivity of semen of HIV-seropositive men warrant further study.

Carbohydrate moieties of small placental hCG: requirement of mannose structure for biological activity

The 43 kDa human chorionic gonadotropin (hCG) (SP-hCG) was purified from human placenta and analyzed for sugar moieties. The low hexosamine content suggests that SP-hCG probably lacks O-linked sugar chains in the beta-subunit and incompletely formed N-linked sugar chains in the alpha- and beta-subunits. In the present study SP-hCG was hydrolyzed with various glycosidases. Treatment of hCG or SP-hCG with O-glycan peptide hydrolase increased the mobility of asialo-hCG beta in reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) while that of SP-hCG beta was unaffected, indicating that SP-hCG beta does not contain NeuNAc-Gal-GalNAc unit. Alpha-Mannosidase and endoglycosidase H hydrolyzed mannose and the high mannose-GlcNAc moieties, respectively, from alpha- and beta-subunits of SP-hCG, but not from the subunits of authentic hCG. Glycopeptidase F hydrolyzed completely the N-linked sugar chains from SP-hCG subunits, producing alpha- and beta-subunits with estimated Mr of 15,000 and 18,500, respectively. The biological activity of purified SP-hCG is about 50-80% of highly purified authentic hCG. In an in vitro system SP-hCG increased cAMP accumulation and testosterone production by rat Leydig cells to the same levels as that induced by hCG. However, the biological activity of SP-hCG was markedly reduced, following treatment with endoglycosidase H or alpha-mannosidase. To attain the level of testosterone production equivalent to that induced with untreated SP-hCG, 10-20 times higher dose of treated SP-hCG was required. On the other hand, cAMP accumulation induced with treated SP-hCG even at a very high concentration was substantially lower than that attained with untreated SP-hCG. In conclusion, the mannose moieties are essential structural components of the hormone in stimulating cAMP accumulation and steroidogenesis by rat Leydig cells.

Prevalence of contraceptive use: trends and issues

This article discusses the sources of data for estimates of contraceptive use, including their reliability and validity. Data from sample surveys and from censuses are presented by countries from the 1960s to the present time. Tables on proportions of users by method of contraception for various time periods are included. The relationship between contraceptive use and level of fertility is also shown. Contraceptive use has increased rapidly in much of Asia and Latin America, but much less so in Arab countries and sub-Saharan Africa. Worldwide, about 400 million of the 800-850 million married couples of reproductive age practice contraception; of these, about 340 million use a modern method. Sterilization is the most widely practiced method of contraception in the world, with tubal ligations far outnumbering vasectomies.

Purification and characterization of an incompletely glycosylated form of human chorionic gonadotropin from human placenta

A small form of hCG (SP-hCG) was purified from an acetone powder preparation of human first trimester placenta by repeated gel filtration and ion exchange chromatography on a Q-Sepharose or FPLC Mono Q column. The estimated mol wt (Mr) of the small hCG by gel filtration is 43K compared to 58K for authentic hCG. The pI of SP-hCG is 10.0, suggesting deficiency of sialic acids. SP-hCG dissociates into subunits when treated with 6 M guanidine-HCl or analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Two beta-subunits of SP-hCG were found with estimated Mr of 23K and 20K. Both are distinctly smaller than authentic hCG beta. A single alpha-subunit was found, with an estimated Mr of 21 K. The immunoactivity (8,900-10,000 IU/mg) of highly purified SP-hCG was comparable to that of reference hCG (CR119) determined by a RIA method using anti-hCG antibodies. The hCG/LH receptor-binding activity of SP-hCG is equivalent to that of reference hCG (CR119). Its biological activity is lower than that of reference hCG (approximately 30% or more) assayed by the in vitro stimulation of rat Leydig cells to produce testosterone and cAMP. A high dose is required to attain the same level of stimulation as reference hCG. The amino acid composition of SP-hCG is similar to that of reference hCG, whereas its hexsamine content is significantly lower. Its glucosamine content is about half that in reference hCG, while it completely lacks galactosamine. These findings suggest that SP-hCG is deficient in O-linked oligosaccharide chain in the beta-subunit, and that the N-linked oligosaccharide chains of both subunits are shortened. SP-hCG is one of the principal forms of the hormone present in first trimester placenta and may be a key intermediate in the posttranslational biosynthesis of hCG. Although it lacks O-linked sugar chains and shortened N-linked sugar chains, it possesses substantial biological activity. To have full biological activity, the hCG molecule must contain the complete complement of sugar chains.

Interaction of gossypol with sperm macromolecules and enzymes

The interaction of gossypol with sperm macromolecules is an important process for the gossypol action. It is of our interests to study the nature of this interaction in order to understand the mechanism of action of gossypol. Our experimental results support the thesis that gossypol inhibits sperm motility by blocking ATP production and utilization. The drug acts on the mitochondria, suppressing oxygen consumption, inhibiting pyruvate dehydrogenase and ATPase activities and probably on the motility apparatus by blocking dynein ATPase activity and preventing protein phosphorylation. The nature of the chemical bond in the interaction of gossypol and macromolecules is through the Schiff base formation and by the hydrophobic and nucleophilic attraction.

Absence of chorionic gonadotropin in sera of women who use intrauterine devices

A controlled study was undertaken to determine whether unnoticed pregnancies routinely occur in users of the intrauterine contraceptive device (IUD). Starting on day 10 of the menstrual cycle and continuing through the onset of menstruation or until the diagnosis of pregnancy, we collected daily blood samples from three groups of normally menstruating young women. The study groups were (A) IUD users (n = 30), (B) women with tubal ligation (n = 30), and (C) women trying to become pregnant (n = 15). The sequential serum samples were analyzed by radioimmunoassay for progesterone (P), human luteinizing hormone (hLH), and human chorionic gonadotropin (hCG). No positive hCG assays in luteal phase blood sera of IUD users were observed. The only positive hCG determinations of IUD users coincided with the preovulatory surge of hLH. Two subjects who became pregnant, as judged by progressive increases in hCG and P levels in the luteal phase, belonged to the group planning pregnancy. The finding of two pregnancies in 15 months of exposure is consistent with the assumption of natural fertility. The probability of no pregnancies in 30 months at risk, as observed among the IUD users, is between 1 in 200 and 1 in 100,000, depending on the assumption made for natural fertility. The study demonstrates that IUD users do not retain their natural fertility, and that IUDs do not exert their antifertility effect as abortifacient agents. If a confirmed pregnancy is detected in an IUD user, it may be assumed to represent an isolated case of contraceptive failure.

Interaction of 14 C-gossypol with human sperm

Gossypol, a bis-sesquiterpene, suppresses spermatogenesis and inhibits sperm motility. The direct interaction of gossypol with human sperm was investigated. Conditions influencing the interaction of 14c-gossypol (radiolabeled on the aldehyde group with specific activity of 3.33 x 10 5 dpm per micromole) with human sperm reached saturation rapidly. Within 1 minute of exposure of motile sperm to 10 uM radiolabeled gossypol at 37 degrees Centigrade, the cincorporation of 14c-gossyol was 17 at 35% at densities of 2.5 x 106 and 8.6 x 106 per ml, respectively. Immobile sperm prepared by heating at 60 degrees Centigrade for 10 minutes incorporated the same amount of 14c-gossypol as motile sperm. Uptake of 14c-gossypol was slightly greater at 37 degrees Centigrade than at 4 degrees Centigrade, and under acidic conditions. To identify the sperm membrane components interacting with gossypol radiolabeled sperm were treated with the following 3 solutions to solubilize the membrane proteins: 0.1% Triton X-100; 1 M urea, 5 mM EDTA in 19mM Tris-HC1, pH 8.3; and 20% sodium doydecyl sulfate (SDS), 0.1M 20mercaptoethanol. The amount of radiolabeled proteins solubilized with respective media were 11, 23, and 67% with specific activities of 1.8 x 103, 2.1 x 105, and 0.3 x 103 cpm per mg protein. The radiolabeled substances solubilized with SDS, mercaptoethanol reagent were separated by gel filtration on Sephadex G-100 column. 3 peaks of radioactivities corresponding to molecular weights of approximately 100, 35, and 25 KD were eluted. The highest radioactivity was found with the 100 KD fraction. The interaction of gossypol with sperm membrane proteins is an early event, followed by inhibition of sperm motility.

Antispermatogenic action of gossypol in men

Twelve Brazilian men were treated with gossypol for 1 year. The treatment schedule consisted of oral administration of 20 mg gossypol daily for 4 months, followed by a maintenance dose of 20 mg on alternate days (3 days a week), totaling 60 mg weekly for 8 months. Ten men became azoospermic at the end of the fourth month of treatment, and the two others developed marked oligospermia with necrospermia. Except for one man who complained of transient listlessness and fatigue, the subjects reported no side effects during treatment. No changes in libido or potency were reported, and plasma testosterone remained unchanged. Blood chemistry values, which included complete blood cell count, cholesterol, glucose, triglycerides, acid phosphatase, urea, transaminases, sodium, and potassium, were not changed significantly during treatment. The response of the pituitary to gonadotropin-releasing hormone stimulation and the response of the testis to gonadotropin stimulation appeared normal in men treated with gossypol. After treatment, the sperm counts reverted to essentially normal levels in 8 of 12 men. In four men, azoospermia continued 1 year after discontinuation of gossypol treatment. Retrograde phlebography carried out in three of the four men who remained azoospermic after discontinuation of therapy revealed subclinical varicocele.

Serum prolactin profiles of normal human conceptual cycles

Commencing on day 10 of the menstrual cycle through onset of subsequent menses, or confirmation of pregnancy, daily sera collected from 15 women planning pregnancy were analyzed by radioimmunoassays (RIA) for prolactin (hPRL), estradiol-17 beta and luteinizing hormone (hLH). Two of the observed subjects became pregnant in the single cycles studied. The profiles of these hormones during the early gestation following spontaneous ovulation were established. No distinct midcycle peaks of hPRL were observed in either subject. Enormous spikes were observed in daily prolactin values, with wide variations between subjects.

Daily serum choriogonadotropin concentrations in early human gestation

Fifteen regularly menstruating, healthy women were studied from day 10 of the menstrual cycle to either confirmation of pregnancy or spontaneous menses. Daily blood samples were obtained and serum luteinizing hormone (LH), human chorionic gonadotropin hormone (hCG), 17 beta-estradiol and progesterone were determined by means of specific radioimmunoassay (RIA). Two of the women experienced spontaneous conception with a rise in hCG on 12 and 13 days after LH peak.

Apparent chorionic gonadotropin immunoreactivity in human non-placental tissues: reduction by protease inhibitors or heat treatment

Thirty-three of forty-one non-placental human tissue samples analysed by radioimmunoassay (RIA) appeared to contain immunoreactive hCG-like material. Tissues with apparent hCG in appreciable quantity were exposed to heat or protease inhibitors to ascertain the contribution of proteolytic enzyme activity to the observed immunoreactivity. Following incubation with protease inhibitor N-alpha-p-tosyl-L-lysine chloromethyl ketone-HCl (TLCK) at a dose that has no effect on the hCG standard curve and reduces the assayable hCG in term placenta by less than 20%, the hCG-like immunoreactivity of testicular and colon tissues was reduced by 39 to 90%. Similarly, heat treatment virtually eliminated hCG-like immunoreactivity of non-placental normal tissues, but had little effect on purified hCG or hCG present in term placenta. The factor present in normal non-placental human tissue giving positive results in the RIA for hCG is not identical to native hCG; it may be proteolytic in nature thus influencing the radioligand assay. The residual immunoreactivity measured following heat treatment of purified hCG increases when anti hCG-beta antiserum is used, but decreases when either anti hCG-alpha or anti-hCG is used.

Comparative prolactin profiles in IUD users and non-IUD users

Starting from the 10th day of the menstrual cycle through onset of the subsequent menstrual bleeding, daily blood samples were collected from 14 women using Copper T IUDs and 10 normal control women. The serum samples were analysed by radioimmunoassay (RIA) for human prolactin (hPRL) and human luteinizing hormone (hLH). hPRL values were subjected to statistics. Episodic patterns of hPRL were observed for all subjects. IUD users show generally lower daily levels of hPRL than non-IUD users, but the apparent differences were statistically insignificant.

A synthetic peptide capable of eliciting antibodies that neutralize human chorionic gonadotropin

Antisera generated to the human chorionic gonadotropin beta-subunit (hCGbeta) have been shown not only to neutralize the biologic activity of hCG but also to cross-react with human luteinizing hormone (hLH). In an attempt to reduce such cross-reactivity, a peptide fragment analogous to the amino acid sequence of the carboxylterminal 45 residues (101-145) of the hCGbeta-subunit with alpha-aminobutyric acid substituting for cysteine at position 110 was synthesized and tested for ability to produce antibodies interacting with hCG. Antisera were generated in rabbits to a conjugate of this peptide with tetanus toxoid emulsified with Freund's complete adjuvant. Antibody titers and specificity were assessed by the double-antibody technique. The results show that the antisera to the synthetic hCGbeta fragment bound 125I-labeled hCG and did not cross-react with hLH in the radioimmunoassay system. Most importantly, the antisera effectively neutralized the biologic activity of hCG as determined by the rat uterine weight assay.

Pituitary-ovarian function after tubal ligation

Pituitary-ovarian function was evaluated by measurement of daily serum levels of luteinizing hormone (LH), 17 beta-estradiol, and progesterone in women with a previous history of tubal ligation. Normally menstruating women served as controls. The duration of the proliferative and luteal phase was similar for both groups. The midluteal progesterone level averages did not differ between the two groups. Preovulatory LH and 17 beta-estradiol peaks were significantly lower in the tubal ligation group; average midluteal LH and 17 beta-estradiol levels were also lower. These results reveal that pituitary-ovarian function can be altered following surgical sterilization.

The menstrual cycle in women using an intrauterine device

The duration and hormonal characteristics of the menstrual cycles of women using Copper T intrauterine devices (IUDs) were studied. Daily load samples were obtained during both the pre- and postovulatory phases of 30 IUD-associated cycles and the hormone values were compared with those of 15 normally menstruating women not using contraception. The ovulation rate and peak levels of 17 beta-estradiol and luteinizing hormone (LH) were not significantly different between the two groups. The average number of days from the 1st day of menstrual bleeding to the LH peak (the proliferative phase) was longer in the IUD users. The number of days from the LH peak to the onset of menstrual bleeding (the luteal phase) was shorter in the IUD users. Because of the compensating nature of these statistically significant differences, the total cycle length appeared to be unchanged. At the time of menstruation, the plasma levels of both progesterone and 17 beta-estradiol were significantly higher among IUD users. It is concluded that the presence of an IUD does not influence ovarian function, but that ovarian steroid production and endometrial events become asynchronous.

Perinatal study in Tientsin: 1978

Clinical records of a total of 3320 singleton births, representing the year 1978, at the two Tientsin Medical College Hospitals, Tientsin, People's Republic of China, were studied to ascertain (a) reproductive parameters such as the average age of the mothers at first and successive births and (b) the relationships between perinatal deaths, prematurity and birth weight and the mothers's age, number of previous pregnancies, parity, maternal conditions in the prenatal and delivery period and operative procedures of delivery.

Large molecular species of chorionic gonadotrophin from human placental tissues: biosynthesis and physico-chemical properties

Human placental tissues in the first trimester of pregnancy were maintained in organ culture and incubated with [3H]proline for 90 min at 37°C. The tissues were homogenized with a protease inhibitor in the buffered medium and separated into subcellular components. A large molecular protein which reacted with antiserum to hCG hCGα and hCGβ, and with the receptor membranes obtained from bovine corpus luteum, was detected in the microsomal component and post-microsomal supernatant fraction. This protein was purified by chromatography on Sephadex G-100, Sepharose-6B and DEAE-Sephadex A-50. The large molecular species of hCG contained high radioactivity and was immunoprecipitated with all three antisera. The purified large molecular hCG was analyzed by electrophoresis on sodium dodecyl sulphate (SDS) polyacrylamide gel. Its molecular weight was estimated to be 90000 daltons. When the large molecular hCG was treated with 8 m urea and mercaptoethanol in the presence of SDS, a major portion of the material dissociated into immunoreactive α and β subunits of rather high molecular weights compared to standard hCG subunits. Under similar conditions standard hCG dissociates completely into its subunits. The present results suggest that the large molecular species of hCG might be a complex composed of larger forms of α and β subunits. This complex might be an intermediary component in the biosynthetic pathway of hCG or a product of posttranslational modification.

Production of choriogonadotropin-like factor by a microorganism

Extracts from an acetone powder preparation of a culture of a microorganism tentatively named Progenitor cryptocides contain choriogonadotropin (CG)-like factor as determined by radioimmunoassay with antiserum to human (h)CG beta subunit COOH-terminal peptide and radioreceptor assay with bovine corpus luteum membranes. Possible interference by proteases in the extracts was excluded. Immunoreactive materials reacting with antisera to hCG beta subunit and hCG beta subunit COOH-terminal peptide were also found in the extracts. No free alpha subunit was detected. The CG-like factor was purified by chromatography on Sephadex G-100, concanavalin A-Sepharose, and DEAE-Sephadex A-50. The factor was adsorbed by concanavalin A-Sepharose, suggesting that it contains mannose and glucose moieties. The factor was eluted at the same position as standard hCG on Sephadex G-100. It dissociated into two bands when subjected to sodium dodecyl sulfate/polyacrylamide gel electrophoresis; the bands corresponded to the respective standard hCG subunits. The biological activity of the purified factor as determined by the rat uterine weight assay and the ovarian weight assay was equivalent to 380 (95% confidence limits: 320-490) and 880 (780-1020) international units/mg, respectively. It can be concluded from the present results that a microorganism produces a glycoprotein that is biologically active and has physicochemical properties similar to those of hCG.

Contraceptive use-effectiveness and the American adolescent

Contraceptive use-effectiveness is significantly shaped by the contraceptors' ages, for pregnancy rates are found to be a function of age. Teenagers are more failure prone than older contracepting women, regardless of method. This higher teenage failure rate can indicate clearly the use-effectiveness of various contraceptive methods. Consequently, both user and method (whether modern or traditional) determine outcome levels of contraceptive use-effectiveness.